I have loosely based this patch series off of the following patch series from Zhang Yi: https://lore.kernel.org/lkml/cover.1536342881.git.yi.z.zhang@xxxxxxxxxxxxxxx The original set had attempted to address the fact that DAX pages were treated like MMIO pages which had resulted in reduced performance. It attempted to address this by ignoring the PageReserved flag if the page was either a DEV_DAX or FS_DAX page. I am proposing this as an alternative to that set. The main reason for this is because I believe there are a few issues that were overlooked with that original set. Specifically KVM seems to have two different uses for the PageReserved flag. One being whether or not we can pin the memory, the other being if we should be marking the pages as dirty or accessed. I believe only the pinning really applies so I have split the uses of kvm_is_reserved_pfn and updated the function uses to determine support for page pinning to include a check of the pgmap to see if it supports pinning. --- Alexander Duyck (3): kvm: Split use cases for kvm_is_reserved_pfn to kvm_is_refcounted_pfn mm: Add support for exposing if dev_pagemap supports refcount pinning kvm: Add additional check to determine if a page is refcounted arch/x86/kvm/mmu.c | 6 +++--- drivers/nvdimm/pfn_devs.c | 2 ++ include/linux/kvm_host.h | 2 +- include/linux/memremap.h | 5 ++++- include/linux/mm.h | 11 +++++++++++ virt/kvm/kvm_main.c | 34 +++++++++++++++++++++++++--------- 6 files changed, 46 insertions(+), 14 deletions(-) --
